Metabolism USMLE Step 1 Practice Question
A 19 year old college student is evaluated after a routine laboratory panel shows total bilirubin of 2.5 mg/dL. He feels well but notes mild scleral icterus during exam week when he often skips meals. AST, ALT, alkaline phosphatase, CBC, and haptoglobin are all normal. Which of the following is the most likely explanation for his jaundice?
Answer choices
- AAbsent bilirubin UDP glucuronosyltransferase activity
- BComplete obstruction of the common bile duct
- CDefective canalicular transport of conjugated bilirubin
- DMildly decreased bilirubin UDP glucuronosyltransferase activityCorrect answer
- EIncreased heme oxygenase activity in macrophages
- FAccelerated heme turnover from hemolysis (G6PD deficiency)
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.